diff --git a/poincare/include/poincare.h b/poincare/include/poincare.h
index 279682893..00e756870 100644
--- a/poincare/include/poincare.h
+++ b/poincare/include/poincare.h
@@ -5,10 +5,12 @@
 
 #include <poincare/absolute_value.h>
 #include <poincare/addition.h>
+#include <poincare/allocation_failed_layout_node.h>
 #include <poincare/arc_cosine.h>
 #include <poincare/arc_sine.h>
 #include <poincare/arc_tangent.h>
 #include <poincare/binomial_coefficient.h>
+#include <poincare/char_layout_node.h>
 #include <poincare/ceiling.h>
 #include <poincare/complex.h>
 #include <poincare/complex_argument.h>
@@ -35,6 +37,7 @@
 #include <poincare/frac_part.h>
 #include <poincare/global_context.h>
 #include <poincare/great_common_divisor.h>
+#include <poincare/horizontal_layout_node.h>
 #include <poincare/hyperbolic_arc_cosine.h>
 #include <poincare/hyperbolic_arc_sine.h>
 #include <poincare/hyperbolic_arc_tangent.h>
@@ -43,6 +46,9 @@
 #include <poincare/hyperbolic_tangent.h>
 #include <poincare/imaginary_part.h>
 #include <poincare/integral.h>
+#include <poincare/layout_cursor.h>
+#include <poincare/layout_node.h>
+#include <poincare/layout_reference.h>
 #include <poincare/least_common_multiple.h>
 #include <poincare/logarithm.h>
 #include <poincare/matrix.h>
@@ -72,6 +78,9 @@
 #include <poincare/sum.h>
 #include <poincare/symbol.h>
 #include <poincare/tangent.h>
+#include <poincare/tree_node.h>
+#include <poincare/tree_pool.h>
+#include <poincare/tree_reference.h>
 #include <poincare/undefined.h>
 #include <poincare/variable_context.h>
 
diff --git a/apps/tree/allocation_failed_layout_node.h b/poincare/include/poincare/allocation_failed_layout_node.h
similarity index 82%
rename from apps/tree/allocation_failed_layout_node.h
rename to poincare/include/poincare/allocation_failed_layout_node.h
index d41c329ed..64f78adf0 100644
--- a/apps/tree/allocation_failed_layout_node.h
+++ b/poincare/include/poincare/allocation_failed_layout_node.h
@@ -1,9 +1,11 @@
-#ifndef ALLOCATION_FAILED_LAYOUT_NODE_H
-#define ALLOCATION_FAILED_LAYOUT_NODE_H
+#ifndef POINCARE_ALLOCATION_FAILED_LAYOUT_NODE_H
+#define POINCARE_ALLOCATION_FAILED_LAYOUT_NODE_H
 
 #include "layout_node.h"
 #include "layout_reference.h"
 
+namespace Poincare {
+
 class AllocationFailedLayoutNode : public LayoutNode {
 public:
   // TreeNode
@@ -18,4 +20,6 @@ public:
   AllocationFailedLayoutRef() : LayoutReference<AllocationFailedLayoutNode>() {}
 };
 
+}
+
 #endif
diff --git a/apps/tree/char_layout_node.h b/poincare/include/poincare/char_layout_node.h
similarity index 87%
rename from apps/tree/char_layout_node.h
rename to poincare/include/poincare/char_layout_node.h
index 329774c7d..c2eee9789 100644
--- a/apps/tree/char_layout_node.h
+++ b/poincare/include/poincare/char_layout_node.h
@@ -1,9 +1,11 @@
-#ifndef CHAR_LAYOUT_H
-#define CHAR_LAYOUT_H
+#ifndef POINCARE_CHAR_LAYOUT_NODE_H
+#define POINCARE_CHAR_LAYOUT_NODE_H
 
-#include "layout_reference.h"
-#include "layout_node.h"
-#include "layout_cursor.h"
+#include <poincare/layout_reference.h>
+#include <poincare/layout_node.h>
+#include <poincare/layout_cursor.h>
+
+namespace Poincare {
 
 class CharLayoutNode : public LayoutNode {
 public:
@@ -56,4 +58,6 @@ public:
   }
 };
 
+}
+
 #endif
diff --git a/apps/tree/horizontal_layout_node.h b/poincare/include/poincare/horizontal_layout_node.h
similarity index 96%
rename from apps/tree/horizontal_layout_node.h
rename to poincare/include/poincare/horizontal_layout_node.h
index 53d332976..4f4647b7c 100644
--- a/apps/tree/horizontal_layout_node.h
+++ b/poincare/include/poincare/horizontal_layout_node.h
@@ -1,10 +1,12 @@
-#ifndef HORIZONTAL_LAYOUT_H
-#define HORIZONTAL_LAYOUT_H
+#ifndef POINCARE_HORIZONTAL_LAYOUT_NODE_H
+#define POINCARE_HORIZONTAL_LAYOUT_NODE_H
 
 #include "layout_reference.h"
 #include "layout_node.h"
 #include "layout_cursor.h"
 
+namespace Poincare {
+
 class HorizontalLayoutNode : public LayoutNode {
 public:
   HorizontalLayoutNode() :
@@ -94,4 +96,6 @@ public:
   }
 };
 
+}
+
 #endif
diff --git a/apps/tree/layout_cursor.h b/poincare/include/poincare/layout_cursor.h
similarity index 94%
rename from apps/tree/layout_cursor.h
rename to poincare/include/poincare/layout_cursor.h
index 0376c24bd..ac4693af3 100644
--- a/apps/tree/layout_cursor.h
+++ b/poincare/include/poincare/layout_cursor.h
@@ -1,10 +1,12 @@
-#ifndef LAYOUT_CURSOR_H
-#define LAYOUT_CURSOR_H
+#ifndef POINCARE_LAYOUT_CURSOR_H
+#define POINCARE_LAYOUT_CURSOR_H
 
 #include "layout_reference.h"
 #include "layout_node.h"
 #include <stdio.h>
 
+namespace Poincare {
+
 class LayoutCursor {
   template <typename T>
   friend class LayoutReference;
@@ -64,4 +66,6 @@ private:
   Position m_position;
 };
 
+}
+
 #endif
diff --git a/apps/tree/layout_node.h b/poincare/include/poincare/layout_node.h
similarity index 96%
rename from apps/tree/layout_node.h
rename to poincare/include/poincare/layout_node.h
index 7aa421a7e..49a8ab656 100644
--- a/apps/tree/layout_node.h
+++ b/poincare/include/poincare/layout_node.h
@@ -1,8 +1,10 @@
-#ifndef LAYOUT_NODE_H
-#define LAYOUT_NODE_H
+#ifndef POINCARE_LAYOUT_NODE_H
+#define POINCARE_LAYOUT_NODE_H
 
 #include "tree_node.h"
 
+namespace Poincare {
+
 class LayoutCursor;
 
 class LayoutNode : public TreeNode {
@@ -64,4 +66,6 @@ private:
   virtual void render() {};
 };
 
+}
+
 #endif
diff --git a/apps/tree/layout_reference.h b/poincare/include/poincare/layout_reference.h
similarity index 91%
rename from apps/tree/layout_reference.h
rename to poincare/include/poincare/layout_reference.h
index 547128dc1..e23a01723 100644
--- a/apps/tree/layout_reference.h
+++ b/poincare/include/poincare/layout_reference.h
@@ -1,9 +1,11 @@
-#ifndef LAYOUT_REFERENCE_H
-#define LAYOUT_REFERENCE_H
+#ifndef POINCARE_LAYOUT_REFERENCE_H
+#define POINCARE_LAYOUT_REFERENCE_H
 
 #include "tree_reference.h"
 #include "layout_node.h"
 
+namespace Poincare {
+
 class LayoutCursor;
 
 template <typename T>
@@ -42,4 +44,6 @@ public:
 
 typedef LayoutReference<LayoutNode> LayoutRef;
 
+}
+
 #endif
diff --git a/apps/tree/tree_node.h b/poincare/include/poincare/tree_node.h
similarity index 98%
rename from apps/tree/tree_node.h
rename to poincare/include/poincare/tree_node.h
index f02f6b6bf..497692629 100644
--- a/apps/tree/tree_node.h
+++ b/poincare/include/poincare/tree_node.h
@@ -1,5 +1,5 @@
-#ifndef TREE_NODE_H
-#define TREE_NODE_H
+#ifndef POINCARE_TREE_NODE_H
+#define POINCARE_TREE_NODE_H
 
 #include <assert.h>
 #include <stddef.h>
@@ -13,6 +13,8 @@
  *  - a reference counter
  */
 
+namespace Poincare {
+
 class TreeNode {
   friend class TreePool;
 public:
@@ -181,4 +183,6 @@ private:
   int m_referenceCounter;
 };
 
+}
+
 #endif
diff --git a/apps/tree/tree_pool.h b/poincare/include/poincare/tree_pool.h
similarity index 98%
rename from apps/tree/tree_pool.h
rename to poincare/include/poincare/tree_pool.h
index 6f6b40c90..83d4cd987 100644
--- a/apps/tree/tree_pool.h
+++ b/poincare/include/poincare/tree_pool.h
@@ -1,11 +1,13 @@
-#ifndef TREE_POOL_H
-#define TREE_POOL_H
+#ifndef POINCARE_TREE_POOL_H
+#define POINCARE_TREE_POOL_H
 
 #include "tree_node.h"
 #include <stddef.h>
 #include <string.h>
 #include <new>
 
+namespace Poincare {
+
 class TreePool {
   friend class TreeNode;
 public:
@@ -172,4 +174,6 @@ private:
   TreeNode * m_staticNodes[MaxNumberOfStaticNodes];
 };
 
+}
+
 #endif
diff --git a/apps/tree/tree_reference.h b/poincare/include/poincare/tree_reference.h
similarity index 98%
rename from apps/tree/tree_reference.h
rename to poincare/include/poincare/tree_reference.h
index f8386b470..9d7556fa4 100644
--- a/apps/tree/tree_reference.h
+++ b/poincare/include/poincare/tree_reference.h
@@ -1,9 +1,11 @@
-#ifndef TREE_REFERENCE_H
-#define TREE_REFERENCE_H
+#ifndef POINCARE_TREE_REFERENCE_H
+#define POINCARE_TREE_REFERENCE_H
 
 #include "tree_pool.h"
 #include <stdio.h>
 
+namespace Poincare {
+
 static inline int min(int i, int j) { return i < j ? i : j; }
 static inline int max(int i, int j) { return i > j ? i : j; }
 
@@ -245,4 +247,6 @@ private:
 
 typedef TreeReference<TreeNode> TreeRef;
 
+}
+
 #endif